Field of the Invention
The present invention relates to a semiconductor device packaged in a module.
Description of Related Art
Conventionally, there is commercialized a sensor module, in which a sensor element and a semiconductor device arranged to generate an output signal corresponding to an input signal from the sensor element (so-called a signal processing LSI) are packaged. In addition, in recent years, a semiconductor device including a nonvolatile memory storing trimming data for adjusting circuit characteristics and communication terminals for making access to the memory is commercialized, and it is under study to package the semiconductor device in a sensor module.
A technique related to sharing of terminals is disclosed in JP-A-2003-188646 and the like. In addition, a technique related to fault diagnosis is disclosed in JP-A-2005-114440 and the like.
The semiconductor device including the nonvolatile memory and the communication terminals can arbitrarily adjust the circuit characteristics by writing the trimming data from outside, and hence can contribute to improvement of accuracy of the sensor module in which the semiconductor device is packaged. However, because of limitation of the number of terminals, a general sensor module is provided with a necessary minimum number of external terminals (power source terminals, ground terminals, and output terminals), and therefore the communication terminals of the semiconductor device cannot be assigned to the external terminals of the memory module. As a result, the nonvolatile memory of the semiconductor device can only be accessed before being packaged in the sensor module, and hence deviation of the circuit characteristics of the semiconductor device due to the packaging cannot be compensated after the packaging.
In addition, conventionally, it is monitored whether or not an output signal of the sensor module is within a normal range for performing failure criterion. However, it cannot be determined whether the failure is in the sensor element or in the semiconductor device only by monitoring the output signal of the sensor module.
Note that the above-mentioned problem can occur also in other modules besides the sensor module.